Electric discharge device



Sept. 6, 1932 c. SPAETH r 1,876,083

ELECTR I C DI S CHARGE DEVICE roriginal Filed March 2. 1929 ("l/0245s JPHHW INVENTOR ATTORNEY Patented Sept. 6 1932 Y UNITED STATESPATENT OFFICE CHARLES SPAETH, OF ELUSHING, NEW YORK ELECTRIC DISCHARGE DEVICE Original application filed March 2, 1929, Serial No. 3 13,5373. Divided and this application filed December 3,

1929. Serial No. 411,277. Renewed January 27, 1932.

This is a division of my copending appli- For liberating the mercury suitable heating ti n Serial No- 343,873, filed March 2, means may be employed in place of the aux- 1929. iliary electrode. This heating means may The invention relates to electrical dis- COIXIPI'iSO y Suitable Source Of @Xtcrhill '6 charge devices, particularly to devic us d heat, but preferably is in the form of a heatfor purposes of illumination. ing coil placed adjacent to the mercury res- It is an object of the present invention ervoir and adapted to be energized by the to provide an electrical discharge tube which discharge current.

is capable of producing a very ellicicnt white When it is desiredto secure a White light 10 light, approximating that of sunlight, the filling Another object is to provide an electrical of the envelope may be of neon gas used discharge illuminating tube I wherein the m (JOI'IJUHCtiOII with a reservoir or other color characteristics of the emitted light may me ns for supplying an exactly proporreadily be modified in a predetermi d tioned amount of mercury vapor. It is ad- 15 nen visable where the tube is to be operated over A further object is the provisio f an a relatively long period of time to maintain electrical discharge tube operating at high the mercury vaporiamg means in operatmn ffi i y d d t d t produce a concenat the correct intensity dur ng the entire optrated brilliant light emission approximat- OFH'BIOII f h (1eV 1ce- It is, however, pos- 20 i li ht sible to start the discharge through the rare In accordance with my invention a radi g (3911111111 and then pp the necessary ant energy emitting discharge device is qh y 9 mercury vapor for a Short PP- onstructed having a of gas at re- I'lOd Of time, after the device duced pressure and a plurality of electrodes continue fi a whlfie g some for conducting an electrical discharge there- AS operatlon 1S contlnhhd the mercury 18 through. For modifying the light emiscleaned UP; pp y elther y condensasion from the device, auxiliary means are 006111551011, s p p some other Ph arranged to add to the gas filling in the de- 11011191111 and the g emltted y t e devlce i d amounts an agent f dif i th gradually reverts to the characteristic color I 30 radiation spectrum. This auxiliary device of the g which in the (32159 y 15 preferably in the fonn of ,3 mercury 1:35. 15 substantially IOd. operating the H1551- ervoir provided with means for liberating X P g' e lCG at the correct H1- mercury vapor. In place of mercury other tenslty u vvap r 1s supplled at the elements or combinations of elements may -same rate at Whlch 15 1150a p d hence 35 be used, for example, cadmium, thallium, the color of the emltted llght remains con- 35- sodium or calcium, depending on the spec- Stanttrum modification desired. For producing other colors of llght, other A preferred f f my i ti f monatomle gases, for example, hel um, arilluminating purposes comprises an envelope gOII, Xenon, crypton, may be used wlth mercontaining an atmosphere of rare gas, such y v p r, r One Of a lnlxture of the rare as neon, and having a reservoir of mercury. gases of a glven characteristic color emiss on V Electrodes are provided for passing a dismay e s d In C0n]unct10n wlth means for charge directly through the rare gas nd liberating a gas or metallic vapor having another electrode for causing a discharge another color'characterlstic. to be passed to the mercury in order to vapo- Other objects and advantages and the manrize it; In order to secure the desired charnor of obtaining them will be made clear actertistics of illumination from the device, in the following specification and accommeans, such as resistances, inductances or panying drawing. capacitances, may be provided for control- In the drawmg, Flg. 1 shows a device con- 50 ling the relative intensities-.of the discharges. structed in accordance with my invention of the emitted specby the passage of a disto a spectrum modifying material;

- the gaseous atmosphere may range anywhere from .1 to 50 millimeters, but I find it preferable to use a pressure in the neighborhood of 6 millimeters. A reservoir for a quantity of mercury 4'is provided in the form of an appendix 5. For energizing the tube the main electrodes 2 and 3 are connected across a suitable source of current 14 by means of conductors 6 and 7. The source 13 may be of either direct or alternating current of a suitably high potential. Connected in series with the conductor 6 is an adjustable resistance 8. For causing discharge to pass to the mercury 4 a connection 9 is made between a lead-1n wire59 sealed through the wall of the reservoir 5 and making contact with the mercury, and the conductor 6. In series with the conductor 9 is an adjustable resistance 10.

In operation a current is caused to pass from the source 13 between the two electrodes 2 and 3, thereby energizing the fillmg of rare gas and causing it to emit light hav ing certain color characteristics. For ex'- ample, Where the rare gas is neon, the light will be predominantly red. In order to modify these color characteristics the resistance .10 is adjusted so that a discharge passes between the electrode 3 and mercury 4, there by causing a quantity of the mercury to be vaporized. The mercury vapor difluses through the gas" in the envelope 1, emitting light rays of its characteristic blue color. By

I properly adjusting the resistance 10 it is pos sible so to balance the blue rays emitted against the characteristic color of the rare gas as to produce a light emission of any desired color. For example, where the rare gas is neon, a proper adjustment of the resistance 10 may be made to cause the emission of white light, the blue rays of the mercury being complementary to the red rays of the neon. The resistances 8 and 10 serve also" as ballast resistances for balancing the negative resistance of the gaseous discharge path. These resistances should thereforenever be cut entirely out of circuit as the discharge current would increase to an excessive value.

While the mercury reservoir is illustrated as positioned near to one of the main electrodes, it need not necessarily be so located. The device will likewise be operative with the reservoir at other positions. By placing the reservoir as shown, the impedance of its discharge path is made relatively large.

Fig. 2 illustrates a lamp adapted for tele vision purposes, the lamp comprising a gas filled envelope 40 having a pair of plate electrodes 41 and 12 spaced apart a distance less than the mean free path of the gas in the Well-known manner. The envelope is filled with an atmosphere of inert gas, for ex- 4 ample, neon and a reservoir 43 containing mercury is provide. In operation, a white light is obtained in the same manner as set forth in connection with Fig. 1. The discharge cannot pass directly between the two plates because of their close spacing and therefore passes around to the outside faces of the plates illuminating them in the wellknown manner.

\Vhere neon gas and an auxiliary mercury electrode are used, as set forth, the color may be adjusted from the characteristic neon color, through white, to the characteristic mercury color. The efliciency of tubes constructed in accordance with my invention is extremely high. For example, when using.

neon gas with mercury vapor to produce a white light, the amount of energy consumed is only about 0.20 watt per spherical candlepower. Because of this relatively high efficieney the amount of heat generated by the device is correspondingly small.

Lamps of this type are substantially silent in operation, especially when direct current is used. They are therefore of great value Where a white, silent and relatively cool, high intensity, illuminating source is desired.

It will be obvious to those skilled in the art that the invention is capable of a wide variety of modifications and adaptations and that the present disclosure is intended merely to illustrate its nature without limiting its scope which is set forth in the appended claims.

What is claimed is:

1. In a television lamp, an envelope, :1 pair of flat electrodes spaced apart a distance less than the mean free path, .a filling of rare gas within said envelope, a reservoir containing mercury connected to said envelope, means for passing a discharge between said electrodes, and means for vaporizing said mercury.

2. In a television lamp, means for producing a broad fiat field of light, said means comprising a pair of electrodes'immersed in an atmosphere of rare gas, and auxiliary means for modifying the color of said light.

3. In a light source, means for producing a broad fiat field of light, said means comprising a pair of broad electrodes positioned modifying material connected to said cm tween said electrodes,

velope, means for passing adischarge beand means for passing a discharge to said mercury.

4; A device in accordance with claim 2, wherein the rare gas comprises neon and the modifying means comprises mercury.

In testimony whereof, I .have signed my name to this specification, this 26th day of November 1929.

' CHARLES SPAETH. 

